1. Field of the Invention
The present invention relates to subsurface imagining of soil and rock properties. More specifically, it relates to a method using electrokinetic transport to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions.
2. Description of Related Art
Many applications require detection of liquid contamination in subsurface soils or rocks. For example, many subsurface gasoline tanks have leaked gasoline for years before the problem was detected. Similarly, holding ponds for liquid toxic wastes and various types of waste landfills have leaked and continue to leak waste. In both of these applications it is highly desirable to detect the existence of a leak and to map the subsurface region through which the waste is moving. Fixing the leaking structure and environmental restoration of the contaminated soils can be made more effectively when this information is available. Subsurface soil and groundwater are generally monitored from boreholes using sensors or obtaining material samples which only represent conditions at points along the borehole wall; these measurements only represent the liquid content of the soil located within inches of the borehole. In order to detect liquid contamination at locations removed from one borehole generally requires the expensive drilling of additional boreholes.